Roller conveyors are well-known in the art, as exemplified by U.S. Pat. Nos. 4,819,788 and 5,042,644, both of which are assigned to Ermanco Incorporated, the assignee of the present application. In roller conveyors, skewed roller sections (i.e., sections where the rollers are at an oblique angle with respect to the conveyor frame) are used along straight runs to urge the articles being transported on the conveyor to one side of the conveyor or the other, depending on the direction in which the rollers are skewed.
In a belt-driven roller conveyor, a single elongated flat belt frictionally engages the bottoms of the rollers to drive or rotate the rollers along a straight run. An exemplary belt-driven roller conveyor is the AccuROL(copyright) conveyor of Ermanco Incorporated.
FIG. 1 is a fragmentary perspective view of a portion of the straight section of an AccuROL(copyright) conveyor system, generally designated 10. The system includes a pair of parallel frame members 12 that support a plurality of rollers 14 which are driven from underneath by frictional engagement with a belt 16. As illustrated, in the straight section, the underside of the belt 16 is supported by a series of guide rollers 18 spaced along the length of the system 10. The belt is on the order of 4 inches in width and is supported on the guide rollers 18 so as to run parallel to the conveyor frame. The bottom of the belt 16 includes a V-guide 16a that is received in a circumferential groove 18a in the guide roller 18. The upper surface of the drive belt 16 is substantially parallel to a plane defined by the axes of the rollers 14, so that substantially the entire width of the belt 16 engages the rollers 14 in order to drive them.
When such a belt-drive encounters a skewed roller section, the forces exerted on the belt tend to cause it to run perpendicular to the axes of the rollers, and thus run off its guide rollers. If the belt has a V-guide integral with its underside for mating with a groove in the guide rollers, the side forces encountered by the belt in the skewed roller section may cause premature wear and separation of the belt.
Accordingly, it is the principal object of the present invention to provide an improved belt guide for the skewed roller section of a belt-driven roller conveyor.
This object, as well as others that will become apparent upon reference to the following description and attached drawings are provided by a belt guide which cants the belt in the skewed roller section of the conveyor so that an edge portion of the belt, and not the entire width, engages the skewed rollers to impart driving motion. This is accomplished by providing a series of free-wheeling xe2x80x9ccam followersxe2x80x9d that support the raised edge portion of the drive belt that contacts the skewed rollers. A second series of freely rotatable grooved wheels or sheaves is provided whose grooved portion captures the lower edge portion of the drive belt.